Adipose Tissue, the tissue in animal bodies containing the largest proportion of adipose substance, known in ordinary language as the fat of the animal, in distinction from the lean or muscular flesh. The adipose tissue is situated principally beneath the skin and over the muscles, particularly those of the abdomen, about the cheeks, in the orbit of the eye, over the buttocks, on the outside of the heart about the origin of the great vessels, over the intestines, where it forms a special layer or distinct curtain called the omentum around the kidneys, and in various places about the inner side of the abdominal walls. It consists of a number of distinct masses or lobules, which are connected with each other by thin layers of areolar tissue, containing the few blood vessels and nerves with which the adipose tissue is supplied, Each lobule in its turn consists of a number of transparent vesicles, or closed sacs, about 1/500 of an inch in diameter, which are peculiar to the tissue and are called the adipose vesicles. Each vesicle consists of a thin, colorless, and structureless animal membrane, embracing a closed cavity, and filled with fluid or semi-fluid fat. The vesicles generally approximate a globular or ovoid form, but with some flattening and angularity of surface produced by mutual compression.

The albuminoid elements entering into the composition of the adipose tissue, such as those composing the wall of the vesicles, the intermediate areolar tissue, etc, are much less abundant than its fatty contents. The blood vessels and nerves are particularly scanty, as compared with those of the neighboring skin and muscles; so that a wound of the adipose tissue produces but slight pain and very little bleeding. - The functions of the adipose tissue are for the most part physical in their character. It acts as a cushion to protect delicate parts from pressure or injury. Particularly, wherever the skin is exposed to frequent pressure over a bony prominence, as over the buttocks or beneath the heel, it is •defended by an elastic layer of fat. The eyeball rests in its socket upon such a cushion of adipose tissue, and the abdominal organs are protected from injurious pressure by that of the omentum and the abdominal walls. The entire layer of adipose tissue beneath the skin and elsewhere also acts as a protection to the animal warmth. Being to a great extent a non-conductor, it is a kind of natural blanket, which prevents the dissipation of the heat of the internal organs, and thus serves to maintain their temperature.

An abundant layer of adipose tissue is accordingly an effective protection against external cold, while animals which are in an emaciated condition more readily suffer from its effects. - Adipose tissue is sometimes deposited in an excessive degree, forming morbid growths or tumors. These tumors, however, are usually not dangerous, but only inconvenient from their size or situation.